Cardiopulmonary resuscitation (CPR) is a procedure performed as life-saving first aid in cases of a sudden cardiac arrest. The procedure comprises performing chest compressions and ventilation. Recent publications have pointed out numerous problems with how CPR is being conducted today by professionals.
Aufderheide et al showed in their publication “Hyperventilation-Induced Hypotension During Cardiopulmonary Resuscitation”, Circulation. 2004; 109 that trained Emergency Medical Services (EMS) personnel had problems ventilating correctly. Even after re-training, the ventilation rate was still too high compared to the “Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care” published by The American Heart Association, in collaboration with International Liaison Committee on Resuscitation (herein after referred to as “the Guidelines”).
Van Alem, Sanou and Koster pointed to another problem with performed CPR in “Interruption of Cardiopulmonary Resuscitation With the Use of the Automated External Defibrillator in Out-of-Hospital Cardiac Arrest”, Annals of emergency medicine 42:4 (October 2003). Even trained EMS personnel that performed CPR conducted compressions or ventilations less than 50% of the time at the scene, i.e., hands-off time/inactivity time was too high.
Two articles in Journal of American Medical Association (JAMA) published Jan. 19, 2005, Vol 293, No. 3, “Quality of Cardiopulmonary Resuscitation During In-Hospital Cardiac Arrest” by Abella et. al. and “Quality of Cardiopulmonary Resuscitation During Out-of-Hospital Cardiac Arrest” by Wik et. al., conclude that hands off time was too high, the correct compression depth was not reached, compression rate was either too low or too high and that hyperventilation happened frequently.
Many CPR assist devices are known. U.S. Pat. No. 6,306,107, Myklebust et al, “System for Measuring and Using Parameters During Check Compression in a Life-Saving Situation or a Practice Situation and Also Application Thereof,” describes such a device. This device does not consider ventilation, ventilation inactivity or compression inactivity.
Another description of a CPR device is described by Halperin et al in U.S. Pat. No. 6,390,996, “CPR Check Compression Monitor.” This device only considers compression. Other, simpler CPR assist devices base their feedback on force and time. One such device is CPREzy from Medteq Innovations Pty. Ltd.
Some CPR assist devices are part of an Automatic External Defibrillator (AED) or a Defibrillator. One such device is part of AEDPlus from Zoll Medical Corporation. That device only considers compressions. Acquiring a new defibrillator with a CPR assist device might not be an option for Emergency Medical Systems (EMS) which already has a well functioning AED/Defibrillator system. Such EMS systems would rather consider a standalone solution for CPR measurement and feedback.
There are no prior art systems or devices that provide feedback on both compression and ventilation activity as well as on inactivity through the full procedure of CPR. These issues are believed to be very important in increasing CPR performance and thus survival rates.
Another problem related to known systems, such as for example the AEDplus from Zoll, is that they are relatively expensive, big, and complicated; so that lay rescuers will not keep them available at all times. Devices made for lay rescuers are described in EP1578340, which describes force sensitive devices giving sound signals for assisting the rescuer, and, more particularly, a device for placement between the hands of a person performing chest compression and the chest of a patient. Even more particularly, the device that is the subject of EP1578340 is designed to emit a sound when chest compression is performed with a force exceeding a pre-defined value and optionally also to emit a sound indicating the desirable rate of chest compression. This is obtained in an inexpensive and compact device which may be battery independent and thus always ready for use, or in the embodiment using a battery having a very low power consumption.
Practice has shown that sound signals in some cases may be difficult to hear, especially in some emergency situations. Also, there is in some instances a need for a more accurate basis for the feedback to the user. If, for example, the applied force is too strong, there is a risk of hurting the patient. Thus there is in such instances a need for an energy efficient and compact device for providing quality CPR feedback, where the feedback is provided in a way that is dependable and likely for the rescuer to receive under all possible situations.